#11 Use more random URLs

[Ant]

At the moment, the URLs of posted images seem to use
yours and your buddy's screen-names with the time
tagged onto the end.

If I know somebody uses ImageIM I could potentially
use a script to generate lots of URLs with different
timestamps in order to view any private images they
have shared with buddy's.

Can we add some randomisation to the URL in order to
avoid this potential breach of privacy please?